There are really 3 things you need to take into consideration when posting a problem. The first, is that the support people aren't telepathic, the second is that the support people are human and the third is that there is a search function.
What I mean by the first, is that if you simply write "HELP!" or "my board's not working" it's very difficult to help you. Generally, it is better to give too much informaton than too little. So when posting, use a descriptive subject and a detailed post. I've created a sample post below which would be more than acceptable

Help! I've been trying to install this thing for hours and can't get it to work.
I'm hosted on prohosting (a paid account rather than their free service)
I'm fairly competent in PHP so I don't believe it's an ID 10-T problem
I downloaded the regular package, and while it manages to extract all the files ok (I checked - they're there), it can't seem to put anything into the database.
The errors I'm getting are of the form "ERROR inserting data package 1", etc...
My database is already created, and I'm sure the username, password and server are correct as I'm runnning a PHP chat in that database too.
I'm running PHP version 4.04, mySQL 3.23. and I don't have phpMyAdmin (the host is annoying that way).
I've tried using the regular and the safemode package, and both generate the same error - and I chmodded everything correctly according to the readme file.
While the post on it's own may not have enough information to diagnose the exact problem, it gives the support people enough to start with.
The second point I made was that the support people are human. That means they can get annoyed and they can take offense. Remember - this is free software, they don't 'owe' you anything, so it pays to be kind when asking for help. A couple things you should do when posting are:
- avoid insulting the support people or the software - generally, this will not make them want to help you
- post in proper language - typos are one thing, but if you post in l33t sp34k or use excessive short-forms like cu etc. it makes it an effort to understand the post
- be patient - the support people do have things to do other than lurk on these boards - many of us have school or fulltime jobs - don't assume we can answer within the hour.
- avoid cross-posting. Generally, it's best to post in one board - posting in multiple boards just annoys people. If you're problem really does affect 2 areas (i.e. templates and other help) then at least have the courtesy to post a link to your cross-post so that when it's solved, the moderators can lock them
The final point I made was that there is a search feature. That means use it

. There is very little more frustrating than having someone make a post about a problem that is already addressed in 50 other posts. Especially when one of those posts is a sticky topic in the help board. Take a minute to search for some relevant posts before blaring your problem everywhere.
So, if you provide a lot of information, and are reasonable in your expectations, you are much more likely to get timely responses.